Regression
by AntebellumHope
Summary: Michelangelo gawked at the relatively large amount of blood that stained several pages of notes as well as the floor.  Some of it was still wet to the touch. A knot was forming in the pit of Leo's stomach.  Something was very wrong with Donatello.
1. Chapter 1

Donatello stared at the large purple and black discoloration on his forearm. He couldn't have said what part of it was a healing bruise and what part was ink from the pen he'd just crushed. One of his precious books was conspicuously absent from the spot on the desk where he'd left it.

_Calm down. You probably put it away unconsciously before dinner._

His nostrils flared and he inhaled deeply, praying his rational mind would smother the irrational rage. Of late, he had been less and less sure of his grip on his temper, and more than once his brothers had suffered the sharp end of his tongue. Leonardo spoke with him as little as possible, just long enough to make sure that he ate and slept. Michelangelo avoided him altogether, except when Splinter paired them off for sparring, and then he either fought dirty or not at all so that the match ended quickly. Raphael, whose temper was now most like his own, tried to reach out to him on more than one occasion, only to have each discussion devolve to blows within minutes.

Donnie sighed, reflecting on the unstable dynamics of his family. A part of him shrugged and chalked it up to them adjusting to life with a more emotional Donatello, but another part - the logical intellect which showed itself less frequently - told him something….something was off.

_You shouldn't be this easily riled up._

That's not to say he didn't have emotions, just that normally, he acknowledged them and moved on. It was out of character for rage or despair or even joy to consume him if the situation did not warrant it. Here lately though, he had become a creature of pure emotion, increasingly unchecked by his stoic nature.

He recalled the concern of his brothers when he slumped into a depression only to come out of it minutes later with a new zeal for life. He spent more and more time in the dojo than in his lab, able to focus on the untapped power of the sinew beneath his skin. He rolled his shoulders at the ache as his muscles cried out for use. He was quickly catching up to and even surpassing Leo in training. Well, physical training at least. As for mental training….

_What is happening to me?_

He physically recoiled as he thought of the numerous times he'd fallen asleep or simply walked out of meditation sessions in the past couple of months. Splinter had been enraged at first, banning him from his own lab for two days and confining him to the dojo when he wasn't eating, sleeping, or using the toilet. But as more sessions were blown off, Splinter's fury lost its edge and slowly dimmed with a rising fear for his son.

Most disconcerting of all was Donatello's own apathy towards the havoc he was wreaking. He made no apologies to his sensei and simply refused his brothers' company for longer than necessary. He couldn't remember the last contact he had initiated with April nor the last time he had tinkered with his experiments. A part of him lamented the few time-dependent experiments that had gone to pieces, and in order to quell that annoying voice, he had come back to the lab to start over. He had been intently reading a passage on DNA and gene suppression when Leonardo tentatively knocked on the door, call him to supper. Irked at the interruption, Donnie nevertheless made a brief appearance at the dinner table. He had downed a small cup of tea and left without a word.

He hadn't told them yet, but there was a reason he had elected not to eat with them. When he felt up to it - that is, when he felt his emotions wouldn't hamper the experiment - he was running diagnostics on himself. The first and possibly most important test was a blood test, and for the greatest accuracy, he needed not to have too much of anything in his system. He had come back to the lab hoping to wait out the hunger and finish the chapter Leo had cut short only to discover the book missing. Futilely searching high, low, and every place in between, his temper showed itself again, resulting in the death of his best pen. He sighed as he went to wash the ink off of his arm.

_Perhaps I need a psych evaluation as well._

_

* * *

_

Leonardo was not happy. He stared down his two loudmouthed siblings, his eyes promising a punishing workout to come for broaching the subject in front of Splinter. If he were in the habit of lying to himself, Leonardo would have denied that his pride was a factor, but in fact is was. He knew that Donatello was reaching the breaking point and would need a listening ear. Leo wanted to be there when his younger brother cracked because he knew he was good at picking up the pieces. However, the second and largest reason for his latest command was so that Splinter wouldn't be unnecessarily troubled.

_"Look, just give me a few more days. He's close; I can feel it." Leo had insisted._

_"But what if it's a few more_ weeks_?" Raphael shot back. "Or what if it's never? Don's pretty good and keepin' real quiet when he wants to."_

_"And….?"_

_"And I think he wants to. Just let him be."_

Leonardo ground teeth now as he had then. Raphael always downplayed everything. Something was seriously wrong with their brother, and he blew it off like one would an annoying bug.

_"Tell me you haven't noticed how much more you both fight."_

_Raphael grudgingly conceded that point only to bring up one of his own. "Tell me you haven't noticed how much you both ignore each other."_

_Leo had talked his pacing and stared down his brother. "I'm….just giving him space. To work through his problems."_

_Raph got in his face. "No, you are doing what the resta us are doing: avoidin' him at all costs. He ain't that much fun to be around anymore."_

_Just as Leonardo would have pushed Raphael out of his personal space, Michelangelo appeared between them. "Stop it! We've got enough fighting going on as it is!"_

_Satisfied that both of his older brothers were looking guiltily at their feet, Michelangelo sat on the floor and looked up at them expectantly. A few moments later, Leo joined him. Raph merely leaned on a support column and raised an eye ridge at his kid brother. Mikey often played peacekeeper when Splinter and Don were absent._

_"Leo, we'll give you three more days. After that, I'm going to Donnie myself. Raph, just hang in there, and if neither of us can get to him, we'll get Splinter involved."_

_Raphael shrugged noncommittally. He hated to admit it, but Mikey usually knew best about this kind of stuff. He easily read all of his brothers and could work out the best compromise. As for Leo, the guilt of having his baby brother disperse yet another fight insured his acquiescence to the request._

So here now, at the dinner table, he was silently fuming at Michelangelo's remark _to Splinter _ about Donatello.

"….I'm not sayin' he's lost it, but somethin's really not right in here." He tapped his own head for emphasis.

Raphael sniggered. "No duh."

"Hmm." Their sensei shut his eyes, no doubt comparing Donnie's current behavior to his past behavior, searching for a possible trigger. "And what of you two?"

The question jolted Leo out of his enraged stupor. "I...I have tried, Sensei." He prayed Splinter overlooked the hesitation in his answer. "But we hardly speak anymore."

Raph snorted, indicating that he, at least, had caught the slight pause in Leo's statement. "He won't talk much ta me either, but when he does, he gets all uptight and I usually hafta _guide_ 'im back to reality."

Splinter groaned inwardly, fully aware of the duel meaning of Raphael's words. "I had not realized things were so out of hand. You should have come to me sooner." He kept a steady gaze on Leonardo as he spoke.

Leo hung his head in shame. "I am sorry, Sensei. I did not wish to worry you."

"Thinking that you must lead this family alone worries me more, my son. Do not doubt the wisdom these many years of life have given me," Splinter softly admonished.

"So what are we gonna do?" Mikey asked.

The old rat closed his eyes again, furrowing his brow. "Let us see what time brings. Do not cease your attempts to reach him. Donatello becomes the most isolated when he is the most troubled, often intentionally. I believe he does not wish to involve us unless he sees no other alternative. Be supportive but be respectful of this need."

"Yes, Sensei." They chorused.

* * *

As he stooped to pick up the stack of notes he kept under his desk, the pain from tension headache broke through and blinded him. Grunting, he shook off the abrupt distraction and hefted the large box onto the work space with a loud_ thud_. He pinched the bridge of his beak, fleshy fingers close to his tear ducts, and rummaged through the cluttered lab looking for pain killers. Headaches were not uncommon to the turtle, especially ones brought on from hours of intense work with little to no food or rest. However, he steadily denied himself drugs unless he was nearly through or the pain halted whatever progress he was making.

Surprised that neither of these reasons seemed to be the case, he rolled the two pills around in his hand before swallowing both of them dry. In a few minutes, he'd likely be drowsy but perhaps a little more like his old self.

_Maybe they'll want to see me in that - what? - four to six hours?_

He smothered his cynical side and hoped he had just tranquilized it. Spots were still dancing in his vision, and he had to clutch the table to keep himself upright. He needed to stay coherent - at the very least_ conscious_ - while he drew and mixed his blood samples.

At the bottom of the cardboard container was an old centrifuge. Setting it out and checking to see that it still had all its parts, Donatello turned his mind to the procedure. It had been a while since he had had to draw blood from himself. On the first attempt, the needle missed the vein entirely and left his whole arm burning. The second time, it fell out leaving a bleeding, swearing Donnie to trying not to dye everything red. The third time was the charm, and soon he had four vials of blood. Gingerly he wrapped up his poor arm and shook each sample to mix in the anticoagulants. He kept a box of crackers and a jar of peanut butter in the lab….somewhere. He sat and munched on the stale snacks for a minute, knowing that four vials may have been overkill. But if he needed more samples for his tests, he really didn't want to have to go through that ordeal again.

The loss of blood made him dizzy and nullified any effect the pain killers were having on his headache, and he soon found himself fast asleep with his head resting on his battered arm.

* * *

Leo was making good on his threat of an intense workout when they were suddenly interrupted by a loud crash fro Don's lab. Raph froze, poised to take a right hook to Mikey's chest when the first obscenity reach their ears. He chuckled at the sudden case of potty-mouth his cleanest sibling had developed. But as the first word led to a string of unusually strong language, including some words Raph didn't even know, the smile shrank and the three turtles exchanged worried glances.

"Should we check on 'im?" Raph kept a wary eye on the lab in the sequestered corner of their home.

"And have all that-" Mikey's gestures indicated the explosion of profanity "-rain down on our heads?"

"We have to do something, though." Leo flushed as his master's words phased through his mind along with the probability that he was about to disobey them. "Doing nothing isn't working."

"What about Splinter?" Raphael seemed as surprised as Leo at the words coming out of his mouth. He was the most unlikely to obey an order, especially when the well-being of one of his family was on the line. But at the same time, he knew what it was like to need privacy.

Leonardo growled in frustration and sheathed his swords. "I don't know."

Michelangelo, who had been uncharacteristically quiet up to this point, spoke so faintly that both of his brothers had to strain to hear him. "What if he hurts himself?"

Afraid at the thought, the three of them burst into the lab unannounced and uninvited, braced for an immediate and thoroughly unpleasant ousting. Met with silence, they cautiously stepped in. Donatello was slumped over his work bench, head on a bandaged forearm. Leo's heart lept into his throat and back down again when was satisfied that Donnie was only sleeping.

"Duuude."

Michelangelo gawked at the relatively large amount of blood that stained several pages of notes as well as the floor. Some of it was still wet to the touch.

"Ya really think Donnie…" Raph trailed off into his thoughts, unaware that his tough guy mask had fallen and that Leo could see the depth of his concern.

He laid an awkward hand on his little brother's shoulder, squeezing it once in an encouraging gesture. "I don't know what to think, Raph."

"Hey!" Mikey called in a whisper. "Don pulled out that blood spinner thing." He pointed to the centrifuge and the thick stack of medical charts and books beside it.

A knot was forming in the pit of Leo's stomach.

_Something is very wrong with Donatello._

He ushered his brothers from the lab as Donnie began to stir himself awake.

_Something is very wrong indeed._


	2. Chapter 2

**Author's Note:** Okay, so this is a fairly short chapter, I know. I'm working out the nitty-gritty details in between classes and work, but I decided to be nice enough to leave this tidbit here for you to savor while you wait for the main course. (Was I taking that analogy a bit far? Sorry. I'm hungry.) As always, read, review, and enjoy! (I would especially appreciate feedback on this particular chapter in relation to the structure of dialogue, description, and overall plot. Shoot, I'll take any plot bunnies that need a good home while I'm at it.)

* * *

Several days had passed since they had snuck into the lab and found the haunting confirmation that Donatello knew. They had not seen much of their brother, only once in fact, when he stormed into the kitchen grumbling about the missing textbook he had left on the counter a few nights before. Leonardo had not hesitated to go to Splinter this time, but that didn't stop the guilt when he saw his master's face fall.

"This is not good." He murmured, more to himself than to his eldest pupil.

"But what can we do, Sensei? None of us are as well read in the medical arts as Donnie. Even if he sought out help, we'd just get in his way."

Splinter sighed. "I do not know, my son."

Those six little words had shaken Leonardo to his core. It wasn't often that some course of action eluded his master. He felt helpless and unsure of himself. He was supposed to help his brothers, take the burden off of his father, not sit there like a...

Splinter's mirthless chuckles brought him back from his dark reverie. "This is not your fault, Leonardo. Sometimes one must accept circumstances out of one's hands." Embarrassed, Leo dipped his head to the hand laid gently on his plastron. "I am sure both the nature of Donatello's malady and a solution will present themselves soon."

Leo silently bowed to his master and rose, lightly shutting the door behind him. The main room was unnaturally still as both Raphael and Michelangelo were out. Raph had gone with Casey on patrol and had dropped Mikey off at April's. April was growing increasingly concerned for her best friend, and Mikey had hoped to ease her suffering somewhat. He sighed and listened to the echo reverberating in the spacious chamber. Donnie had holed up in his lab again, leaving the dojo to Leo.

_I wonder if he's eaten anything yet._

Don was growing thin and gaunt from lack of nutrition. Leo paused in front of the laboratory doorway. The door itself was swinging half open.

"Don?" He called cautiously. Startling Donatello was high on his list of things _not_ to do right before he died. "Donnie?"

Again, there was no answer. The sixth sense he had developed was drumming a groove into the base of his skull. Something was off. He stepped into the lab and shielded his eyes from the many lights and computer screens. Donatello was nowhere to be seen.

"Donatello!"

Leo balled his hands into fists, a nervous reaction carried over from childhood. He carefully - very carefully for he did not want to break anything of value - circled the lab. All of a sudden, the floor came rushing at him. On reflex, he braced his arms for impact and nearly shattered his wrists.

_What on earth?_

He wasn't sure what he had fallen over and was too preoccupied with his stinging palms to care. It was bulky and long, nearly five feet. Half hidden in shadow, a piece of it had come away and fallen in between Leo's feet. Curious...it's silhouette was strikingly similar to…

"DON!"

Donatello moaned weakly. His breaths were raspy and uneven, and he looked a shade or two paler than usual. His eyes darted frantically to Leo, his work bench, back to Leo, and then to various spots in the lab before rolling back in his head.

"Don! Donnie!" Leo patted the side of his face a bit harder than was absolutely necessary. No response. Panicking, he lifted his brother's painfully light frame into his arms. He was more relieved than he should have been to hear a muffled whimper as Donatello nuzzled closer to his plastron. Leo laid him on the couch in the main room.

"Don't try to sit up." He ordered.

"Gotta…" was the slurred reply.

"Thirsty?" A shaky nod. "Lemme help you up, and I'll bring water." More nodding.

Leo was surprised that he was able to hold on to the glass. The ice cubes rattled against the edges as it shook in his trembling hands. He tipped his brother's head back, supporting his neck as he drank. After a few huge gulps, the glass was drained and some color had returned to Donnie's face.

"What happened?" Leo started as Raphael's voice cut sharply through the air.

"...n-nothing…" Don's quiet answer was drowned out by Leo's own.

"He passed out."

Donatello sighed and rested the back of his head on the couch, groaning in embarrassment. "I...just haven't eaten enough. It was just a small dizzy spell."

Leonardo and Raphael cast a dubious eye on their sibling as Michelangelo strolled into the living room, stripping himself of his riding gear as he went. The look in his eye as his gaze fell on the resident genius bordered on repugnance. "Keep on lying like that and your teeth will shatter, y'know."

Leo laid a hand on Don's knee to keep him from leaping off the couch. "Look, just...just tell us what's going on. We can't help you -" he held up a hand to stop Donnie's retort "- we get that." He paused until Don met his eyes. "But don't carry this alone."

"Fine." The word barely made it through Don's lips, a sure sign of frustration. "I'm sick."

Leo, Raph, and Mikey stilled. They all knew he was unwell, but to have him admit made it real, made it tangible. Made it horrifying. They gathered around to hear his small voice.

"I'm sick," he repeated, "but I don't know with what. I don't think it's contagious, or you all would have been presenting symptoms by now. I've been doing a myriad of tests on myself, but so far, nothing is conclusive."

Raphael snorted in unbelief. "Well, usually when ya reach the point of callin' down curses on yer stuff, you've got an idea. So let's hear it."

Surprised and angered that he'd been caught, Donatello gave a sharp "Hmpf!" before picking himself up off the couch and began pacing, a definite indication that whatever he was about to share would be unpleasant. Michelangelo unconsciously reached a hand out toward him, willing him to stay upright as he swayed. The hand was instantly retracted as Don spoke.

"I...I think I'm regressing, turning back into...a monster."


End file.
